Properties

Label 1258.a.21386.1
Conductor 1258
Discriminant 21386
Mordell-Weil group \(\Z/{10}\Z\)
Sato-Tate group $\mathrm{USp}(4)$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q\)
\(\overline{\Q}\)-simple yes
\(\mathrm{GL}_2\)-type no

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Minimal equation

Minimal equation

Simplified equation

$y^2 + xy = x^5 + 4x^4 - 5x^3 - 4x^2 + 5x - 1$ (homogenize, simplify)
$y^2 + xz^2y = x^5z + 4x^4z^2 - 5x^3z^3 - 4x^2z^4 + 5xz^5 - z^6$ (dehomogenize, simplify)
$y^2 = 4x^5 + 16x^4 - 20x^3 - 15x^2 + 20x - 4$ (minimize, homogenize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-1, 5, -4, -5, 4, 1]), R([0, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-1, 5, -4, -5, 4, 1], R![0, 1]);
 
sage: X = HyperellipticCurve(R([-4, 20, -15, -20, 16, 4]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  \(=\)  \(1258\) \(=\) \( 2 \cdot 17 \cdot 37 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(21386\) \(=\) \( 2 \cdot 17^{2} \cdot 37 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(9440\) \(=\)  \( 2^{5} \cdot 5 \cdot 59 \)
\( I_4 \)  \(=\) \(818368\) \(=\)  \( 2^{6} \cdot 19 \cdot 673 \)
\( I_6 \)  \(=\) \(2401900480\) \(=\)  \( 2^{6} \cdot 5 \cdot 7 \cdot 83 \cdot 12919 \)
\( I_{10} \)  \(=\) \(87597056\) \(=\)  \( 2^{13} \cdot 17^{2} \cdot 37 \)
\( J_2 \)  \(=\) \(1180\) \(=\)  \( 2^{2} \cdot 5 \cdot 59 \)
\( J_4 \)  \(=\) \(49492\) \(=\)  \( 2^{2} \cdot 12373 \)
\( J_6 \)  \(=\) \(2427545\) \(=\)  \( 5 \cdot 485509 \)
\( J_8 \)  \(=\) \(103761259\) \(=\)  \( 7 \cdot 3469 \cdot 4273 \)
\( J_{10} \)  \(=\) \(21386\) \(=\)  \( 2 \cdot 17^{2} \cdot 37 \)
\( g_1 \)  \(=\) \(1143878878400000/10693\)
\( g_2 \)  \(=\) \(40658469872000/10693\)
\( g_3 \)  \(=\) \(1690056829000/10693\)

sage: C.igusa_clebsch_invariants(); [factor(a) for a in _]
 
magma: IgusaClebschInvariants(C); IgusaInvariants(C); G2Invariants(C);
 

Automorphism group

\(\mathrm{Aut}(X)\)\(\simeq\) $C_2$
magma: AutomorphismGroup(C); IdentifyGroup($1);
 
\(\mathrm{Aut}(X_{\overline{\Q}})\)\(\simeq\) $C_2$
magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
 

Rational points

All points: \((1 : 0 : 0),\, (1 : 0 : 1),\, (1 : -1 : 1)\)

magma: [C![1,-1,1],C![1,0,0],C![1,0,1]];
 

Number of rational Weierstrass points: \(1\)

magma: #Roots(HyperellipticPolynomials(SimplifiedModel(C)));
 

This curve is locally solvable everywhere.

magma: f,h:=HyperellipticPolynomials(C); g:=4*f+h^2; HasPointsEverywhereLocally(g,2) and (#Roots(ChangeRing(g,RealField())) gt 0 or LeadingCoefficient(g) gt 0);
 

Mordell-Weil group of the Jacobian

Group structure: \(\Z/{10}\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(x^2 + 2xz - z^2\) \(=\) \(0,\) \(y\) \(=\) \(3xz^2 - z^3\) \(0\) \(10\)

2-torsion field: 6.6.2803712.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(0\)
Mordell-Weil rank: \(0\)
2-Selmer rank:\(1\)
Regulator: \( 1 \)
Real period: \( 20.93152 \)
Tamagawa product: \( 2 \)
Torsion order:\( 10 \)
Leading coefficient: \( 0.418630 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(1\) \(1\) \(1\) \(( 1 - T )( 1 + 2 T + 2 T^{2} )\)
\(17\) \(1\) \(2\) \(2\) \(( 1 - T )( 1 + 2 T + 17 T^{2} )\)
\(37\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 - 8 T + 37 T^{2} )\)

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $\mathrm{USp}(4)$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{USp}(4)\)

Decomposition of the Jacobian

Simple over \(\overline{\Q}\)

Endomorphisms of the Jacobian

Not of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)\(\simeq\)\(\Z\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q\)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).